Satellite communications systems may be used to facilitate global exchange of information. In particular, significant growth is expected in the future for satellite communications in the higher transmission frequencies range (Ka-Band at 20-30 GHz), and at higher data rates. As one example, Low Earth Orbit (LEO) satellites typically require high transmission frequencies. These LEO satellites may be linked to each other and to ground based stations to provide wireless access over the surface of the Earth.
In order to communicate with the LEO satellites and other high frequency satellites by tracking them with an antenna, rigorous tracking requirements may have to be met. As a first step, the positioner for the antenna may have to be capable of precise, full-hemispherical tracking.
Conventional two-axis full-motion antenna positioners may have operational keyholes, or cones of silence, when tracking Low Earth orbiting (LEO) satellites. Although some three-axis designs may overcome many of the keyhole issues, they may still require relatively high velocity and acceleration capabilities. Some configurations may also be operationally constrained by the ground station latitude and satellite inclination angle.
There is a need for an antenna positioner system that can provide full hemispherical coverage without keyholes, for any satellite inclination angle and for any ground station latitude location, while minimizing the tracking velocity and acceleration requirements.